Northeast Michigan field crop regional report – June 9, 2016
Pests threaten first cutting alfalfa and wheat.
Weather and rainfall
Approximately 0.55 inches of rain fell at the Michigan State University Hawks Enviro-weather station in the last week, mainly on Sunday, June 5. The precipitation was needed, with topsoil moisture being less than adequate in many fields just prior. Our next chance for rain will come Saturday, June 11, as thunderstorms delivering perhaps 0.10-0.25 inches. A cold front will then move through early next week, bringing scattered showers Monday, June 13, followed by a string of five to six dry days that are expected to carry us through next week. The 6-10 and 8-14 day outlooks from NOAA suggest our region will likely experience below normal rainfall for some time after forecast showers pass.
Growing degree days (GDD)
Temperatures have been unseasonably cool over the last seven days, with daytime highs ranging from 60 to 76 degrees Fahrenheit and nighttime lows of 39 to 53 F. GDD accumulations since March 1 total 1,358 base 32 F, 783 base 41 and 403 base 50. Most of our region is zero to seven calendar days ahead of the 30-year average for GDD accumulation at this point in the season. Areas within a few miles of the lake average three days behind normal, however.
Temperatures are expected to increase moving into the weekend ahead, with highs reaching the low 80s on Saturday, June 11. Temperatures will then dip slightly Monday, June 13, before climbing steadily through the mid- to upper 70s during the remainder of next week. The 6-10 and 8-14 day outlooks from NOAA call for a significant chance of above normal temperatures in the medium term.
Harvest of first cutting alfalfa is beginning tentatively in our region. Plants are 17 to 26 inches tall in the early bud stage of growth. Neutral detergent fiber (NDF) concentrations are in the range of 30-36 percent. With moist and cool conditions prevailing over the last several days, much of what has been harvested will be wrapped and ensiled. Harvest of mixed and grass hay will likely begin next week, and a string of warm, clear days in the forecast should offer good drying conditions.
Mounting alfalfa weevil pressure has caused concern among growers over the last week, particularly since weather has precluded early cutting for dry hay. If weevil numbers are high, causing significant damage, growers can consider harvesting early to control the pest. If the threshold for alfalfa weevils is reached and the crop is not scheduled to be harvested within the next seven days, an insecticide application may be warranted. However, all available products have a pre-harvest interval of one to 21 days, so they must be selected carefully. Beneficial insects can also be affected by pesticide applications in forages.
Winter wheat in northeast Michigan is heading, and will begin flowering in the next week. Signs of common fungal leaf diseases, including Septoria and powdery mildew, are present in a few areas, but pressure is limited. However, stripe rust infections are also being reported in our region.
According to MSU Extension wheat educator Martin Nagelkirk, this pathogen can be particularly aggressive, reducing wheat yields by at least one-third in severe cases. Variety susceptibility is important in managing this disease. About one-third of Michigan wheat varieties have limited resistance. A fungicide application is recommend where stripe rust is found on susceptible varieties. A list of recommended fungicides can be found in “Fungicide Efficacy for Control of Wheat Diseases” by MSU Extension. If the disease is found just prior to a scheduled application of Caramba or Prosaro fungicide at flowering for head scab prevention, no additional fungicide product or application is necessary. For more information, contact Nagelkirk at firstname.lastname@example.org or MSU plant pathologist Martin Chilvers at email@example.com.
Most of the corn crop in northeast Michigan has emerged and ranges in development from spiking to three true leaves (VE-V3). Emergence appears to be uniform in most fields, but the young plants are generally light in color. The lack of green color is likely the result of cool temperatures limiting root growth and nutrient uptake. Crop condition and development should improve quickly as average temperatures increase moving into the second half of June. Black cutworm numbers appear to be low overall this season, with only one larva trapped per week on average at our monitoring site near Rogers City, Michigan.
Soybeans are approximately 90 percent emerged in our region. Earlier planted stands range in development from the cotyledon stage through one fully unrolled trifoliate leaf (VC-V1). Rain last weekend was especially welcomed where soybeans had been planted into dry soil. Post-emergence herbicide applications are being made in soybeans and corn, but the recent cool weather has limited activity in some cases. Full rates of AMS and surfactant are recommended to improve herbicide activity. For any soybean acres yet to be planted, growers should consider switching to a maturity group 0.5 or 1.0 unit shorter than normal.
Potato growers in northeast Michigan have mostly completed their planting operations, and shoots are emerging in fields planted a couple of weeks ago. Blackleg, an early season bacterial disease of potato, has been reported in southern Michigan. Growers are encouraged to scout fields for stunted, chlorotic or wilted plants, particularly if seed was sourced from the East Coast where recent infections are thought to have originated.
Dry bean planting is now underway in our region. Our local dry bean variety trial will be planted in the next few days near Hillman, Michigan, carried out in partnership with ADM Edible Bean. The trial will include seven varieties in four classes including blacks, navy beans, small reds and great northern beans.